A heterogeneous enantioselective oxa-Michael–Michael reaction for the synthesis of chromans has been developed on a heterogeneous acid–base synergic catalyst with inherent silica as acidic sites and immobilized chiral amines as basic sites. Final products were afforded in selectivity of up to 98% and ee of 97% from 2-nitrovinyl phenol and 3-methyl-2-butenal. The heterogeneous synergistic catalytic mechanism has also been studied.

Layered double hydroxides (LDHs) are a class of clays with brucite-like layers and intercalated anions which have attracted increasing interest in the field of catalysis. Benefiting from the atomic-scale uniform distribution of metal cations in the brucite-like layers and the ability to intercalate a diverse range of interlayer anions, LDHs display great potential as precursors/supports to prepare catalysts, in that the catalytic sites can be preferentially orientated, highly dispersed, and firmly stabilized to afford excellent catalytic performance and recyclability. The approaches to prepare catalysts based on LDH materials include, but are not limited to, exfoliation of the brucite-like layers, lattice orientation/lattice confinement by the brucite-like layers, and intercalation. This Feature Article summarizes the latest developments in the design and preparation of nanocatalysts by using LDHs as precursors/supports.

Layered double hydroxides (LDHs) are a class of clays with brucite-like layers and intercalated anions which have attracted increasing interest in the field of catalysis. Benefiting from the atomic-scale uniform distribution of metal cations in the brucite-like layers and the ability to intercalate a diverse range of interlayer anions, LDHs display great potential as precursors/supports to prepare catalysts, in that the catalytic sites can be preferentially orientated, highly dispersed, and firmly stabilized to afford excellent catalytic performance and recyclability. The approaches to prepare catalysts based on LDH materials include, but are not limited to, exfoliation of the brucite-like layers, lattice orientation/lattice confinement by the brucite-like layers, and intercalation. This Feature Article summarizes the latest developments in the design and preparation of nanocatalysts by using LDHs as precursors/supports.